Thursday, April 9, 2009

Human Migrations: Were Harappans Indigenous or Migrants?

Harappan age - 2500 BC to 2000 BC - graves with skeletal remains along with pottery and other artifacts have been discovered at a site in Farmana, Haryana about 60 km from Delhi. There are 70 graves discovered so far say researchers from the Deccan College Post Graduate and Research Institute Pune. The graves are part of a big housing complex, a sign of urbanization of Harappan society by 2500 BC.

The lead researcher Vasant Shinde on this discovery:

“With a larger sample size it will be easier for scholars to determine the composition of the population, the prevalent customs, whether they were indigenous or migrated from outside,”

“DNA tests on bones might conclusively end the debate on whether the Harappans were an indigenous population or migrants.

The DNA testing is to be done at the The Research Institute for Humanity and Nature, Kyoto Japan.

Well good luck to finding out whether these people are indigenous or migrated from outside. Whether someone is indigenous or a migrant depends on the time line you choose. In terms of migrations that may have left a distinct cultural impact of Indian societies, a convenient dividing line would be to regard people entering India before the Holocene as indigenous and those that entered India after the advent of agriculture post Holocene i.e. after around 8000 -10,000 years ago as migrants. So far the genetic profiles of Indian populations tell a complex and mixed story. Mitochondrial DNA evidence indicates that modern humans have been resident in India /south Asia from as early as 60,000 years ago. In that sense Indian people are indigenous to this region. The story gets complicated though. A recent study of the genetic profiles of south Indian castes shows that whether a particular sample shows an entirely indigenous character or affinity towards Eurasian or SE Asian populations depends upon which genetic material you are looking at.

If you take total ancestry measures using autosomal genetic material then Indian subpopulations are more closely related to each other than to European or S E Asian populations. That would indicate that castes and subpopulations have a common origin and underwent a long period of differentiation from Eurasians and SE Asians . This accords well with the MtDNA date of a very early human presence in India. The genetic distance map below shows Indian populations cluster together and are seen to be genetically distant from European and SE Asian populations, although SE Asians seem more like an outgroup.

Source: via Gene Expression - Genetic variation in South Indian castes: evidence from Y-chromosome, mitochondrial, and autosomal polymorphisms

But if you take only say the paternal ancestry using certain Y chromosome genetic variants then an affinity toward Western Eurasian populations is seen among even south Indian castes.

Source: via Gene Expression - Genetic variation in South Indian castes: evidence from Y-chromosome, mitochondrial, and autosomal polymorphisms

This suggests gene flow mediated by migrations of males between Indian and Eurasia. This is a highly controversial finding as people would immediately point out to the migration of Indo-Aryan speaking people from Iran / Central Asia and elite dominance as the event which has caused this pattern. This affinity though is visible only within a particular type of variant on the Y chromosome . The majority of Indian Y chromosome variants show very high diversity which indicates that they are quite old, certainly pre-Holocene and arrived here before historically documented human diffusion between Eurasia and India. So evidence of exogenous gene flow in historical times is an overlay on an essentially Indian genetic substrate. The fact is that Harappan society which most historians agree is pre-Aryan shows plenty of evidence of cultural exchanges with Eurasia. Artifacts point to trading links between Harappan people and Iran and Mesopotamia. And it is likely that males played a bigger role in these trading ties. Indian deep history and more recent history has always been a story of people migrating, of cultural diffusion and .. of gene flow.

I doubt whether DNA analysis will definitely tell whether the Harappans were either totally indigenous or rank outsiders. My money is that they were like the rest of us living Indians, mostly native but with little pieces from outside as well.


  1. Great work.

    I enjoy your posts.


  2. I hope people take this objectively

  3. >> end the debate on whether the Harappans were an indigenous population or migrants

    Was there any doubt on whether Harappans were indigenous ? If so what is the basis of such a doubt ?

    Those who erroneously equate, Harappan civilization with Vedic literature, are already touchy about Arya-speaking people being referred as external migration.
    Such a doubt about the Harappan indigenousness, will add to their distrust of the objectivity of the opinion opposite to theirs

  4. good point Khalil. there is an eagerness to show the indigenous nature of all people. Certainly the Harappans to my knowledge were never consider migrants as the Indo-Aryan speakers have been.